Debt - Additional Information (Detail)	3 Months Ended		6 Months Ended			6 Months Ended				6 Months Ended				6 Months Ended				6 Months Ended
	Jun. 30, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2012 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2013 Term Loan [Member]	Dec. 20, 2011 Term Loan [Member] USD ($)	Jun. 30, 2013 Chinese Credit Facility [Member] USD ($)	Dec. 31, 2012 Chinese Credit Facility [Member] USD ($)	Jun. 30, 2013 Chinese Credit Facility-BOA [Member] USD ($)	Jun. 30, 2013 Chinese Credit Facility-BOA [Member] CNY	Sep. 30, 2012 Chinese Credit Facility-BOA [Member] USD ($)	Sep. 30, 2012 Chinese Credit Facility-BOA [Member] CNY	Jun. 30, 2013 Chinese Credit Facility-JPM [Member] USD ($)	Jun. 30, 2013 Chinese Credit Facility-JPM [Member] CNY	Apr. 30, 2012 Chinese Credit Facility-JPM [Member] USD ($)	Apr. 30, 2012 Chinese Credit Facility-JPM [Member] CNY	Jun. 30, 2013 Revolving Credit Facility [Member] USD ($)	Dec. 20, 2011 Revolving Credit Facility [Member] USD ($)	Jun. 30, 2013 Letters Of Credit [Member] USD ($)	Jun. 30, 2013 Borrowings On Same Day-notice [Member] USD ($)
Debt Instrument [Line Items]
Maximum borrowing limits							$ 600,000,000					$ 30,000,000	189,000,000
Term Loan Facility, principal amount	360,000,000		360,000,000				400,000,000
Period of Term Loan Facility							5 years												5 years
Borrowings, maturity date						Dec. 01, 2016												Dec. 01, 2016
Borrowing capacity under Revolving Credit Facility																			200,000,000	40,000,000	40,000,000
Borrowings, interest rate description			Interest at LIBOR plus 175 basis points, or the Eurocurrency Spread, or the alternate base rate ("ABR") plus 75 basis points
Borrowings alternate base rate			0.75%			1.75%				100.00%	100.00%			100.00%	100.00%
Commitment fee on undrawn amount			0.30%
Borrowings, interest rate basis						2.00%				5.60%	5.60%			5.60%	5.60%
Principal repayment of term loan			2.50%
Principal payments on long-term debt			20,000,000	10,000,000
Revolving Credit Facility borrowings	24,633,000		24,633,000		32,145,000					11,300,000				13,300,000				0
Total interest and commitments fees	2,000,000	2,100,000	4,100,000	4,400,000
Short term borrowings outstanding								24,600,000	32,100,000
Extended revolving credit facility of Chinese subsidiaries with BOA										22,000,000	138,600,000					20,000,000	125,000,000
Revolving credit facility, maturity term										1 year	1 year			1 year	1 year
Payment of interest on Chinese Credit Facilities										$ 10,900,000	68,283,570.0			$ 3,900,000	24,281,546
Interest rate of Chinese Credit Facility BOA										Chinese Credit Facility-BOA currently bears interest at a rate based on 100% of the People's Bank of China's base rate and was 5.6% as of June 30, 2013.	Chinese Credit Facility-BOA currently bears interest at a rate based on 100% of the People's Bank of China's base rate and was 5.6% as of June 30, 2013.			Chinese Credit Facility-JPM currently bears interest at a rate based on 100% of the People's Bank of China's base rate and was 5.6% as of June 30, 2013.	Chinese Credit Facility-JPM currently bears interest at a rate based on 100% of the People's Bank of China's base rate and was 5.6% as of June 30, 2013.